Mold for casting steel articles.



C. G. ROBINSON.

MOLD FOR CASTING STEEL ARTICLES.

,APPLICATION FILED JAN. go, 1913.

Patented July 18, 1916.

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C. G. ROBiNSON.

MOLD FOR CASTING STEEL ARTICLES.

APPLICATION FILED JAN. 20, ms.

1 1 9 l ,474. Patented July 18, 1916.

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CHARLES of ROBINSON, or PITTSBURGH, PENNSYLVANIA, AS-SIGNOR T0 HARRY SHELDON, OF PITTSBURGH, PENNSYLVANIA.

M OLD FOB, CASTING STEEL ARTICLES.

Application filed-January 20, 1913.

To all whom it may concern:

Be it known that I, CHARLES G. ROBINSON, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Molds for Casting Steel Articles, of which the following is a specification.

My invention relates to molds for casting steel articles.

While my invention is not limited to any definite article, I have chosen a cast steel railway. tie as illustrative of an article made in the mold, hereinafter tobe described.

It has long been desired to manufacture a cast steel railway tie in such a manner that it would stand the strains to which it is peculiarly subjected in use. I believe that I have solved this problem with the result that cast steel railway ties can be produced at a price not merely to compete with wooden ties, but also of a quality which enables it to increase the safety and durability of railway construction, and to enable railway engineers to figure with certainty as to its ca pability. I have discovered that the re liability and strength of a cast steel railway tie depend very largely upon casting it under certain conditions and have constructed a mold wherein it maybe cast under such conditions. In my mold, certain surfaces, into contact with which the metal flows, are stable in the sense that the metal can fiow by them at maximum speed and without affecting them detrimentally.

'More specifically, in my mold the said surfaces are stable only while the flow of metal continues, having sufiicient instability thereafter to permit the rapid cooling of the cast metal without producing any strains thereon that would impair the reliability of the tie.

More specifically still, in my mold the said surfaces are such that their instability after the flow of metal has ceased is due to their fragile character, whereby theyare quickly and easily broken by the strains of cooling and, therefore, afford substantially no resistance to the said strains.

More specifically still, the said surfaces are composed of hollow fragile ,material.

More specifically still, the said surfaces are protected against fusing or other dele- Specification of Letters Patent. I PatenfiedJ 1 5118 1916 Serial No. 743,042.

Yterious action by the heat derived from the molten metal by the combination with the place. Figs. 3 and 4 are enlarged cross-sections, of Fig. .1 on the lines IIIIII and I'VIV, respectively, showing the conditions after the pouring of the metal has been completed and beforethe cast article has contracted. Figs-5, 6, and 7 are perspective views of three of the fragile surfaces above. referred to. Fig. 8 is a longitudinal section similar to the left-hand end of Fig. 2, but showing a modification.

Indescribing my invention I shall not describe in detail the article to becast as it is the subject-matter of the application of George W. Snyder, Serial Number 724,097, filed October 5th, 1912-. In this specification I shall describe only such parts of the rail- -way-tie as illustrate the principles of my in vention.

The mold which I prefer-is composed of a top section 1, a-bottom section 2,- and a few smaller sections to be pointed out hereinafter. The sections 1 and 2 are each preferably made of a single piece of steel. The section 2 is provided with the channels and recesses, which determine the form of all portions of the tie except its bottom surface and the projections depending therefrom, the bottom surface and the said projections being molded by the section 1. The tie is cast bottom side up, thejhorizontal base of the tie being cast in the passage 3 in the section 2, the top wall of the passage being formed by the bottom surface of the section 1. Fig. 1 shows the mold constructed to cast two ties simultaneously. The passage 3 is shown to be narrow at the central portion -3 but the end portions thereof are made wider as shown at 3*. V The passage 3 forms the narrowportionfi of the base of the tie (Figl) and the passage 3" forms the in dotted lines inclined irregularly passage l.

wide end portions of the base (Fig. The passage 3 communicates from one end to the other with the vertical passage 4: which lies under the passage 3 and forms the web 5, shown in section'on Figs. 3 and l. The lower limits of the passage l at the end portions of the mold section 2 .are indicated from the ends toward the center.

In the section 2 there is the horizontal passage 8 parallel with the passage 3, the passage 8 lying below the passage 4: with which it communicates. The passage 8 terminates at each end a short distance above the inner ends of the dotted lines 4. The

passage 8 forms the upper flange of the tie, which flange is narrow at 9 in the central or connecting portion of the tie (Fig. 4), and wider at 9 opposite the wider portion of the passage 3 (Fig. 3). The wider portion (marked 8) of the passage 8 shaping a rest or seat for the railway rail.

here are numerous lateral passages 10 extending right and left from the vertical The lateral passages form stif ening ribs or braces 11 (Fig. 3) for the web and the flanges 6, 7, 9, and 9. On

that side of each of the lateral passages toward which the ribs or braces 11 move when the web 5 and the flanges 6, 7, 9, and 9 contract, that is, on the side of the lateral passages toward the center of the mold, I place unstable surfaces, in contact with which the molten metal flows and sets.

' These surfaces are stable while the flow of the metal continues but yield so as to relieve the strains on the ribs as the said web and flanges contract and move the ribs toward the center of the mold, or longitudinally of the said web and flanges. These surfaces are preferably made of fragile material which is quickly and easily broken by the pressure of ribs as they creep toward the center of the mold. Preferably these unstable, yielding, fragile surfaces are made hollow and are composed of glass, terra cotta, or their equivalent, but I do not limit my invention to any particular material, as many materials may be used or formed to make the aforesaid surfaces. 1 have marked these surfaces or the elements bearing them with the numeral 12. They have their ends seatedin recesses in the section 2 so as to maintain them in a fixed position during the flow of the metal in contact therewith. As shown in Fig. 3, the hollow elements 12 may be left open sided at those places where no metal is to be cast or flowed in contact therewith.

The passages 8 communicate at each end with the downwardly extending transverse passages or recesses 13 in which are formed iupstanding ribs or projections 14 shown in dotted lines on Fig. 3. The surfaces of the 55 passages or recesses toward the center of the 5. On the left hand side of this figure the left hand half of the flange 9 is occupied by the hollow fragile element 12*, which is located as shown in Fig. 1 to form the side of the recess 15 nearest the center of the mold.

The top section of the mold has its bot tom recessed to form lugs on the bottom of the base. Some of these recesses, as 16, ea tend longitudinally of the tie, the ends thereof nearest the center of the mold being provided with the unstable, yielding, fragile elements 12 (Fig. 7 and dotted lines, Figs. 1 and 2). Others of the said recesses, as 17, extend transversely of the tie and have the sides thereof nearest the center of the mold occupied by the unstable, yielding, fragile elements 12 (Figs. 6 and 3, and dotted lines, Figs. 1, 2, and 3). 1n the recesses 16, are cast the lugs 16 and in the recesses 17 are cast the lugs 17. I place other fragile elements 12 (Figs. land a) in the mold to form surfaces to form the shoulders or edges 19 which taper toward the center of the mold or the narrow portions 3 of the passage 3. p

In order that the tie may be removed from the section 2, it is necessary that pertions of the same between the passages 3 and 8 be removable. I have shown the longitudinalunetal"fillers or blocks 20 arranged to form the inner faces of the flanges 6 and 9 and spaced apart to form the web 5 (Fig. 1). Other removable metal blocks 20 are located between the end portions of the passages 3 and 8 so as to shape the flanges 7 and 9 and the web 5 to be formed there.

()n Fig. 8, I have shown the hollow fragile element 12 separated from the recess 13 at the left thereof by the slidable metal block 20", against the left edge of which the metal is cast. The contraction of the tie causes the metal cast in the left recess 13 to push the block 20 to the right, thereby breaking the element 12. 21 represents the vertical central runner and 22 the horizontal branch runners in the mold section 2 leading from the runner 21 to central'portions of the passage 3. At the junction of each runner 22 with a passage 3 the mold section 1 is provided with the recesses 23 for the cutting tool 2&, which may be driven downwardly, thereby cutting off the metal in the runners before the removal of the casting from the mold section 2. The tool 2 1 has therein a transverse hole 25 in which a pin may be inserted to hold the lower end of the tool above the runner until it is desired to cut off the metal in the runners 22.

The metal of the mold conducts away the heat from the cast metal at such a rate as to prevent the fusion of the transient or fragile elements 12 to 12. By the use of a steel mold provided with thick walls, the metal may be poured at maximum speed into the same without any danger of fusing the transient material and with the result that the metal cools uniformly. When the tie contracts, the ribs and projections, which are cast in contact with the transient fragile material 12 to 12 quickly break the said material which opposes practically no resistance to the travel of ribs and projections, so that all the ribs and projections on the tie are formed without strains or fracture and are substantially as strong as the web and flanges and substantially uniform, so far as strains are concerned, with the web and flanges.

In Fig. 2, it will be noted that the two recesses 13 nearest the center of the mold are undercut or inclined downwardly and toward the ends of the mold. The metal cast in these undercut recesses 13 moves, when the casting contracts, toward the center of the mold, thereby freeing the flanges cast in the recesses from the overhanging metal.

I claim 1. In a device for casting metallic articles, a mold comprising a plurality of parts which compared with each other are respectively permanent and fragile, the permanent part being composed of a good heat-conducting material adapted and constructed to convey away the heat from the casting so as to prevent the fusion of the fragile part and the fragile part being arranged to'be broken by the shrinkage of the casting.

2. In a device for casting metallic articles,

a mold comprising a plurality of parts which compared with each other are respectively permanent and fragile, the permanent part being composed of a good heat-conducting material adapted and constructed to convey away the heat from the casting so asto prevent the fusion of the fragile part and the fragile part being composed of hollow glass arranged to be broken by the shrinkage of the casting.

3, In a device for casting metallic articles, a mold having at least one face composed of hollow fragile material in combination with an adjacent good heat-conducting material, whereby heat tending to fuse the fragile material is removed and the fragile material is broken by the shrinkage of the casting.

4. In a device for casting metallic articles, a mold having a solid, coherent, hollow nonflexible fragile surface forming a part of the core of the mold, the said surface comprising a material which disrupts upon the shrinking of the cast metal, thereby permitting a ready release of the casting.

5. In a device for casting metallic articles with ribs, a mold having the surface thereof which forms the ribs composed of a solid, coherent, fragile glass surface which disrupts upon the shrinkage of the cast metal to permit the ready release of the casting.

Signed at Pittsburgh, Pa., this 14th day of January, A. D. 1913.

CHARLES G. ROBINSON.

Witnesses:

ALICE E. DUFF, F. N. BARBER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

